I think overall you have a good eye for composition. I'd say on most of them, your time of day for shooting is off... try not to shoot betweek 11 am - 3 pm; the sun is directly overhead and it tends to flatten the subjects.
Concrete -- I would have like to seen it shifted slightly to the left so we get a little bit more view of the regressing horizon on the right side; also, maybe get a little higher so as to cut some of the fluorescents out.
Tractor1 -- is a nice subject, you have a little vignetting. The sky is a little uninteresting, so I'd maybe focus a little more on the subject; maybe reshoot at dusk with clouds in the sky...
Autumn trees -- has great potential, again, shoot when light is softer; cut out stuff on right side of frame, the interest is in the leafy corridor.
Farm -- is a neat subject, might benefit from a different composition. I.e. different perspective, maybe shoot from the other side, or with the wreckage on the right in the foreground...
Trees -- is nice; shoot at different time of day, shift frame to left to cut out some of the unnecessary strip mall on the right...
Old deli -- easily my favorite; the shadow adds interest, but I think the exposure is slightly off... I know you want the hard shadow, but I'd like to see this one also without the harsh overhead light; it could benefit from something small in the foreground (a discarded box, bull trashcan, etc...)
Please take these comments for what they are, constructive criticism. I love to see people get into creative photo, your photos remind me a lot of what I used to do in my early years of college.
I think you have a strong eye for subject, and a good eye for composition. Work on exposure a little (remember that unless your subject is 20 percent gray tone, that your camera meter isn't giving you the right exposure, adjust up or down a little as necessary). Also, as a rule, shoot outside of that harsh overhead light (although it can work for some things).
GREAT JOB! Thanks for sharing!